Baa may be forced to sell Edinburgh or Glasgow Airport as a result of an investigation by the Competition Commission.

An interim report said the company was failing to serve passengers and suggested there was room for competition between Scotland's biggest airports.

However, a final decision will be delayed until the full findings are published in August.

Most airlines believe a break-up of BAA's monopoly on major airports - including Aberdeen, Edinburgh, Glasgow, Heathrow and Gatwick - would be good for the industry.

Bmi boss Nigel Turner said: "The only option facing the regulators is the dismantling of BAA's monopolistic grip over the UK's busiest airports.

"Only with separate airport ownership can the UK guarantee a healthy and competitive aviation industry to serve the wider consumer interest."

EasyJet chief executive Andy Harrison said the report was "a major step in the right direction" and added: "The combination of awful service, massive price increases and antiquated infrastructure makes it obvious to millions of passengers that the UK's major airports are a shameful mess."